ch 6 study questions

Which is NOT a correct attribute of a metabolic pathway?

A constant supply of new enzymes must be produced to keep the metabolic pathway active.

Which statement most accurately describes the second law of thermodynamics?

Energy cannot be changed from one form to another without a loss of usable energy.

If an enzymatic reaction was controlled by feedback inhibition, we would expect it to stop

as soon as a critical level of end product builds up.

The main reason that ATP is considered the energy currency in cells is because it

contains accessible energy in phosphate bonds.

If you wished to increase enzyme activity, you would do all of the following except

decrease the temperature.

In this diagram, the cell on the left

has a less stable configuration. has more potential energy. is more organized.

In this diagram, the molecule on the left

has a less stable configuration. has more potential energy. is more organized.

Enzymes are specific. This means that they

have a particular substrate.

Each enzyme has a particular substrate because enzymes

have active sites complementary in shape to their substrates.

The function of an enzyme is to

increase the rate of a metabolic reaction.

Which of the following can act a an enzyme cofactor?

iron, vitamines, NAD+

In which of the following ways is the enzyme inhibitor warfarin used?

rat poison anticoagulant medicine

Occasionally someone claims to have built a machine that can run forever, producing as much energy as it consumes. This has always been disproved because it violates

the second law of thermodynamics.

In feedback inhibition of a metabolic pathway, where does the inhibitor bind?

to the enzyme of the first reaction

Which is true about energy of activation?

Adding the correct enzyme can lower the energy of activation.

Which of the following statements is not true concerning enzymatic activity?

As the temperature increases, most enzymatic reactions will still proceed at the same rate.

Which of the following is NOT a correct statement about the second law of thermodynamics and entropy?

Carbon dioxide and water form glucose without the input of energy.

Which of the following statements most accurately describes the first law of thermodynamics?

Energy can be neither created nor destroyed but it can be changed from one form to another.

If you give a child a surgary snack you might notice that they become hyperactive right afterward. Much of the sugar in the blood can be quickly absorbed by the neuronal cells of the brain where the glucose is quickly broken down to create ATP. This is an example of which factor affecting rates of enzymatic reactions?

Substrate concentration

While paddling your canoe down a river you notice many turtles laying on logs in the sun. This is an example of which factor affecting rates of enzymatic reactions?

Temperature

During an enzymatic reaction, what happens to the enzyme?

The enzyme and the substrate form a temporary complex.

Which of the following statements is true about enzymes?

They catalyze only one specific type of reaction.

We often say that we need food for energy. In a biological sense, is this correct?

Yes, because the food we eat has potential energy in its structure and this chemical energy can be converted into mechanical energy.

Some metabolic reactions require that one molecule undergoes a reaction that causes it to lose energy and that energy is then transfered to a new chemical bond on another molecule. This describes

a coupled reaction.

If A -> B -> C -> D -> E represents a metabolic pathway, then letter E would be

a product

The location in which the enzyme and substrate complexes is called the

active site.

ATP contains

an adenine base, a ribose sugar, and three phosphate groups.

This image demonstrates the second law of thermodynamics in that

the animal loses some energy to heat when chemical energy is converted to mechanical energy.

The high energy bond in ATP that is used by cells is found in or between

the phosphate groups.

This image demonstrates the first law of thermodynamics in that

the plants convert light energy from the sun to chemical energy.